Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 251450
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1050 AM EDT MON MAY 25 2015

.SYNOPSIS...
HIGH PRESSURE WILL SLIDE FARTHER EAST INTO THE ATLANTIC...TAKE ON A
MORE SUMMER-LIKE BERMUDA HIGH PATTERN...AND REMAIN THERE THROUGH THE
WEEK. THIS WILL PRODUCE A MOIST SOUTHERLY FLOW WITH INCREASED
CHANCES FOR WIDESPREAD SHOWERS AND THUNDERSTORMS EACH DAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT...LOW CLOUDS CONTINUE TO EXPAND ACROSS THE REGION
ON THE STRENGTH OF MOIST SOUTHERLY FLOW AT LOW LEVELS. THE LOWER
CLOUD BASES WILL SLOWLY LIFT WITH HEATING BUT BECOME AUGMENTED BY
CONVECTIVE CUMULUS TO KEEP SKIES CLOUDIER THAN NOT AT MOST LOCATIONS
THROUGH THE DAY. STILL...WARMING THICKNESSES WILL PERMIT PLENTY OF
MAXES IN THE 80S THROUGHOUT...WITH UPPER 70S IN MOST MTN VALLEYS.

THE CONVECTION ALLOWING MODELS...PARTICULARLY RECENT RUNS OF THE
HRRR...ARE NOT ESPECIALLY EXCITED ABOUT CONVECTIVE COVERAGE THIS
AFTERNOON GIVEN THE WEAK CAPPING IN PROFILES TO THE W AND STRONGER
CAPPING OVER THE PIEDMONT. STILL ANTICIPATE SOME LATE DAY
DEVELOPMENT FORCED MAINLY BY PARCEL LIFTING OVER THE TERRAIN IN SRLY
UPSLOPE FLOW. IMPROVING PRECIPITABLE WATER IN PROFILES WILL LEAD TO
HEAVY RAINFALL WITH ANY SHOWERS AND THUNDERSTORMS THAT FORM...BUT
PROFILES DO NOT APPEAR UNSTABLE ENOUGH TO SUPPORT MUCH OF A SEVERE
THREAT...ESPECIALLY WITH THE CLOUDINESS AROUND.

ALTHOUGH THE CONVECTION WILL EXHIBIT A MAINLY DIURNAL TREND...IT
COULD WELL LINGER THROUGH THE NIGHT ACROSS THE WRN CWFA WHERE
ADDITIONAL SHORT WAVE ENERGY AND UPPER DIVERGENCE WILL MOVE THROUGH
IN THE SWLY FLOW ALOFT. LOWS TONIGHT WILL BE NEARLY 10 DEGREES ABOVE
NORMAL.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...MODELS IN GOOD AGREEMENT THAT AN AXIS OF HIGH
PWAT AIR WILL STALL ACRS THE CWFA...AS HIGH-AMPLITUDE UPPER RIDGE
REMAINS ANCHORED JUST OFF THE EAST COAST...WHILE A DE-AMPLIFYING
TROF NUDGES EAST. THE CONFLUENT FLOW BETWEEN THESE FEATURES HELP
KEEP PWATS HIGH. BOTH THE NAM AND GFS FCST SNDGS SHOW FAIRLY MOIST
PROFILES WITH WEAK SHEAR AND POTENTIALLY SLOW STORM MOTIONS. UPPER
FORCING REMAINS FAIRLY WEAK...BUT EMBEDDED SHORTWAVE IMPULSES WILL
CROSS THE AREA WITHIN GRADUALLY INCREASING SWLY FLOW ALOFT. SO
EXPECT LARGELY DIURNAL PULSE CONVECTION...WITH LOCALLY HEAVY RAIN
BEING THE MAIN THREAT BOTH TUESDAY AND WEDNESDAY. ALTHO SOME
LINGERING NOCTURNAL CONVECTION IS EXPECTED BOTH TUESDAY AND
WEDNESDAY NIGHTS...WITHIN THE MOIST AIR MASS. POPS WILL BE IN THE
LIKELY TO CATEGORICAL RANGE FROM THE FOOTHILLS WEST...AND GENERALLY
MID TO HIGH CHC EAST. TEMPS WILL BE ABOUT A CATEGORY OR TWO ABOVE
NORMAL FOR AFTN HIGHS...AND ABOUT 6-8 DEG ABOVE NORMAL FOR OVERNIGHT
LOWS.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...A SHORTWAVE TROF WILL GET SHEARED OUT AS IT
TRIES TO BREAK DOWN THE UPPER RIDGE ALONG THE APPALACHIANS ON
THURSDAY. THE UPPER RIDGE REASSERTS ITSELF ACRS THE REGION SOMEWHAT
BY FRIDAY...AND CONTINUES TO DOMINATE OVER THE SOUTHEAST STATES THRU
THE WEEKEND. OVERALL...THE AREA REMAINS FAIRLY MOIST AND
HUMID...WITH A BERMUDA HIGH PRES SYSTEM REMAINING ANCHORED OVER THE
NORTH ATLANTIC. NEAR OR SLIGHTLY ABOVE NORMAL TEMPS AND CONTINUED
DIURNAL POPS (LIKELY MTNS AND CHC PIEDMONT) ARE EXPECTED THURSDAY
AND FRIDAY. THEN TEMPS WARM A CATEGORY OR TWO FURTHER UNDER THE
BUILDING UPPER RIDGE...WITH POPS A LITTLE LOWER...BUT STILL ABOVE
CLIMO FOR THE WEEKEND.

&&

.AVIATION /15Z MONDAY THROUGH FRIDAY/...
AT KCLT...SCATTERED STRATOCUMULUS AND EARLY DAY CONVECTIVE CUMULUS
NEAR THE AIRFIELD WILL LIKELY LEAD TO A DECK RIGHT AROUND 3 KFT
THROUGH THE LATE MORNING HOURS. THERE SHOULD BE ENOUGH EARLY DAY
HEATING TO BURN OFF CIGS AND KEEP THIS COVERAGE SCATTERED FOR THE
MOST PART...THEN STEADILY RISING THROUGH THE DAY WITH MIXING.
ANTICIPATE STEADY SRLY FLOW AT 8 TO 10 KT...BUT WILL OMIT ANY GUSTS
SINCE THE BETTER SPEEDS ALOFT SHOULD NOT MIX DOWN DUE TO DECENT
CAPPING. THE SUBSIDENCE INVERSION MAY WEAKEN LATE IN THE DAY...BUT
WITH ANY SCATTERED CONVECTION LIKELY WRAPPING WEST OF THE PIEDMONT.
THERE SHOULD BE A MUCH BETTER CHC OF RESTRICTIONS TONIGHT WITH
GUIDANCE IN GOOD AGREEMENT ON LOW CLOUDS DEVELOPING. EXPECT MVFR
CIGS NEAR MIDNIGHT AND IFR SOON AFTER. SLY WINDS CONTINUE THRU THE
PERIOD.

ELSEWHERE...MVFR CIGS WILL CONTINUE TO STEADILY LIFT AND SCATTER
THROUGH THE LATE MORNING HOURS ACROSS THE MTNS AND FOOTHILLS...WITH
MAINLY CONVECTIVE CUMULUS FILLING BACK IN THROUGH THE AFTN TO
PROVIDE VFR CIGS. PROB30 HAS BEEN RETAINED FOR ALL BUT HKY WHERE
ATMOS REMAINS CAPPED OR TIME CONSTRAINTS DO NOT ALLOW. KAVL TO KAND
COULD SEE THE BEST CHANCE OF A LATE DAY SHRA/TSRA. MVFR CIGS RETURN
ALL AREAS AROUND MIDNIGHT...WITH MVFR VSBY AT KAVL AS WELL. IFR CIGS
DEVELOP SOON AFTER. STEADY S TO SE WINDS ARE EXPECTED THROUGH THE
PERIOD.

OUTLOOK...MOISTURE WILL CONTINUE TO RETURN OUT OF THE SOUTH THROUGH
THE MIDDLE OF THE WEEK. INCREASED MORNING STRATUS...AND BETTER THAN
CLIMATOLOGICAL CHANCES OF MAINLY AFTN/EVE SHRA/TSRA ARE EXPECTED
THROUGH THU. HOWEVER...PASSING UPPER LEVEL DISTURBANCES COULD DRIVE
A FEW STORMS AT NIGHT.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-12Z
KCLT       HIGH 100%     HIGH 100%     HIGH  94%     HIGH  90%
KGSP       MED   63%     HIGH 100%     HIGH  80%     HIGH  90%
KAVL       MED   73%     HIGH 100%     MED   79%     HIGH 100%
KHKY       LOW   55%     HIGH 100%     HIGH  92%     MED   76%
KGMU       MED   66%     HIGH 100%     MED   78%     HIGH  88%
KAND       HIGH  80%     HIGH  98%     MED   69%     HIGH  85%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...ARK/HG
NEAR TERM...HG/RWH
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...HG/RWH


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